The jolly actor-screenwriter is perched on the stage of a makeshift Muppet Theater that’s been erected inside a mammoth Universal Studios soundstage. He’s nervously grimacing while the furry blue daredevil Gonzo the Great winds his arm up in preparation to launch a bowling ball toward Segel for a stunt the pair are filming for “The Muppets.”

Segel, who co-wrote the movie with “Forgetting Sarah Marshall” director Nicholas Stoller, is balancing more than just a bowling pin on his head these days: The Walt Disney Co., which acquired The Muppets franchise from The Jim Henson Co. in 2004, has entrusted him with the first big-screen adventure starring the felt-covered performance troupe in 12 years.

“I think at some point, The Muppets changed a little bit,” said Segel during a break from filming earlier this year. “Our goal with this movie is to reintroduce The Muppets to kids in a way that’s reminiscent of the movies from the late ‘70s and early ‘80s. The great thing about those movies and what Pixar does now is they don’t pander or condescend to children.”

Segel, a hardcore Muppet fan best known for his R-rated roles in such movies as “Knocked Up” and “I Love You, Man,” petitioned Disney brass to resurrect The Muppets with Stoller in a way that would appeal to both nostalgic adults who grew up watching “The Muppet Show” and children more familiar with computer-generated 3-D animation than big-eyed puppets.

In the film, out Wednesday, Segel and Amy Adams play a small-town couple named Gary and Mary who — along with Gary’s puppet brother Walter (portrayed by Peter Linz) — work to reunite The Muppets. It seems the felt ones have found themselves irrelevant in an entertainment landscape dominated by such over-the-top fictional game shows as “Punch Teacher.”

The musical’s story line mirrors The Muppets’ own reality. They haven’t starred in a film together since the 2005 made-for-TV movie “The Muppets’ Wizard of Oz” and have been absent from theaters since 1999’s “The Muppets in Space.”

“It’s funny that the success of the movie might undo the story itself,” said director James Bobin. “That’s what actually drew me to the story. I was struck by how honest it was and with real artistic license portrayed how people perceive The Muppets at this time. One of the great emotional drives in any story is getting the band back together.”

The new movie finds The Muppets off doing their own thing: Fozzie Bear is languishing in a tribute band called The Moopets, Miss Piggy is sashaying around Paris as a fashion editor, Animal is treating his anger management issues at rehab, Dr. Teeth and The Electric Mayhem are performing in the New York subway and Scooter is working at Google.

The filmmakers, most of whom have never worked with puppets, let alone The Muppets, closely collaborated with the puppeteers who have been portraying these characters for years. One particular meeting with them led Segel and Stoller to axe any self-referential jokes and puns about The Muppets being puppets. “I wonder how that felt,” for example, was a goner.

“We’re all partners on this movie,” said producer Todd Lieberman. “We grew up on The Muppets, but these guys have been living it for 20 years. They know these characters better than any of us possibly could because they’ve been doing it for 20 years. They know the characters, and they know the style. They know what to do and what not to do for the brand.”

Adams, who ran the award show gauntlet earlier this year for her role in “The Fighter,” found it more difficult to switch between flashy gowns at night and Mary’s conservative ensembles by day during production than working with puppets. She said acting opposite puppets like Walter wasn’t any more difficult than working opposite actors like Mark Wahlberg.

“Once you accept that the puppet that you’re working with is an actual character, it really is no different from working with another human actor,” said Adams. “The puppeteers are geniuses at disappearing. I don’t know how they do it, but they do it. I see Peter and Walter as two completely separate beings. Peter is Peter, and Walter is Walter.”

The immersive set design helped, too. For the new Muppet Theater that’s supposed to look like it’s abandoned until The Muppets give it a makeover, production designer Steve Saklad and his team incorporated the towering theater set built in 1924 for “Phantom of the Opera,” which is still standing inside a soundstage on the Universal Studios backlot.

“We were originally going to shoot the parts of the Muppet Theater scenes that face the audience in a historic downtown Los Angeles theater, but it would’ve been limiting for the director to split everything up,” said Saklad. “I think it worked out for the best because now we’ve got this huge, luscious theater covered in a thousand coats of paint.”

Saklad said the new Muppet Theater set was put in storage after production on “The Muppets,” just in case it’s required for a sequel, and he’s hoping that no one paints over the “Phantom of the Opera” walls. However, the prospect of The Muppets as a rejuvenated franchise featuring Segel is one the actor-screenwriter can’t seem to fathom.

“That would certainly be amazing,” said Segel sheepishly. “It’s not something I’m even thinking about right now. I’m still focused on this movie. My big goal was just to re-establish The Muppets where they belonged. From there, everything else is gravy. I just wanted to see The Muppets again the way I remembered them.”